77945447 has 2 divisors, whose sum is σ = 77945448. Its totient is φ = 77945446.

The previous prime is 77945443. The next prime is 77945449. The reversal of 77945447 is 74454977.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 77945447 - 2² = 77945443 is a prime.

Together with 77945449, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (77945443) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38972723 + 38972724.

It is an arithmetic number, because the mean of its divisors is an integer number (38972724).

Almost surely, 2^77945447 is an apocalyptic number.

77945447 is a deficient number, since it is larger than the sum of its proper divisors (1).

77945447 is an equidigital number, since it uses as much as digits as its factorization.

77945447 is an evil number, because the sum of its binary digits is even.

The product of its digits is 987840, while the sum is 47.

The square root of 77945447 is about 8828.6718706723. The cubic root of 77945447 is about 427.1662353877.

The spelling of 77945447 in words is "seventy-seven million, nine hundred forty-five thousand, four hundred forty-seven".